CN102323656B - High-frequency response two-dimensional micro angular deflection control reflector based on double-shaft flexible hinge - Google Patents

Abstract

The invention discloses a high-frequency response two-dimensional micro angular deflection control reflector based on a double-shaft flexible hinge, and belongs to a light beam control device. The high-frequency response two-dimensional micro angular deflection control reflector based on the double-shaft flexible hinge comprises a reflector, a two-dimensional deflection mechanism based on the double-shaft flexible hinge, a drive mechanism and a control system, wherein the reflector is fixedly assembled on a rigid platform of the two-dimensional deflection mechanism based on the double-shaft flexible hinge; an incident light beam is emitted after being reflected by the reflector; and the control system controls a positive micro drive mechanism and a negative micro drive mechanism to push the rigid platform at a high speed along a negative position and a positive position respectively at symmetric positions, so that the reflector on the rigid platform deflects at a micro angle to realize the direction control of the emitted light beam; and a displacement sensor of the control system feeds the rotation angle information of the reflector back to a computer system to adjust the micro deflection angle of the reflector in real time. The high-frequency response two-dimensional micro angular deflection control reflector based on the double-shaft flexible hinge has the characteristics of no-coupling and no-axial translation in a two-dimensional deflecting direction, and high response speed.

Description

High-response two-dimensional micro-pendulum control mirror based on biaxial flexible hinge

technical field

The invention belongs to the technical field of beam control, and mainly relates to a high-response two-dimensional micro-angle pendulum control reflector based on a biaxial flexible hinge.

Background technique

Micro pendulum control mirrors are often used in optical systems to control the rapid angular deflection of light beams and realize the direction correction and stabilization of light beams. For example, in the adaptive optics system, it is used to correct the overall tilt of the beam front; in the field of wireless optical communication technology, it is used to achieve the alignment and stability of the beam; Tracking; used in the field of high-energy lasers and precision collimation to stabilize the beam direction. In the application of these optical systems, in order to improve the beam control accuracy and obtain good compensation, tracking and control effects, it is required that the beam fast deflection control device must have high angular deflection sensitivity and fast response capability, that is, high angular sensitivity and high frequency response. , and in some occasions such as laser radar, it is required to have a large angular scanning range at the same time.

At present, the rapid deflection control method of the beam includes a mechanical beam deflector. The traditional mechanical beam deflector is mainly realized based on a universal joint or a flexible hinge structure, and is currently a widely used beam deflection method.

The gimbal structure is to install the reflector on the gimbal, and the rotation of the gimbal drives the reflector to deflect the outgoing beam at any angle. The advantage of the gimbal structure is that it can deflect the beam at a large spatial angle, but To control the deflection of the light beam with this gimbal structure requires the operation of the entire rack. Due to the large inertia of the rack structure, narrow frequency band, and slow response, it is difficult to achieve high precision. It is only suitable for medium precision or low speed. Beam deflection control in case.

The micro-angular pendulum control mirror based on the flexible hinge structure has the characteristics of compact structure and no friction loss. The piezoelectric ceramic or voice coil motor driver is used to push the flexible hinge or directly push the mirror to achieve angular deflection. Due to the high displacement sensitivity of the piezoelectric Ceramic or voice coil motor drivers can achieve very high beam deflection sensitivity, but their response speed during fast deflection is often limited by the resonant frequency of the flexible hinge itself. How to improve the resonant frequency of the flexible hinge is a problem that needs to be studied, and the flexible hinge When the structure performs two-dimensional angular deflection, it is easy to generate coupling in the two-dimensional deflection direction.

Li Xinyang and others from the Institute of Optoelectronics Technology, Chinese Academy of Sciences made a two-dimensional high-speed tilting mirror with asymmetric structure supported by a single point of flexible support. Based on the measurement data, a dynamic mathematical model of the mechanical resonance of the high-speed tilting mirror was established, and a network filtering technology was proposed to reduce the tilt. The mechanical resonance of the mirror greatly improves the control stability and control bandwidth of the high-speed tilting mirror. However, this method does not solve the problem of mechanical resonance from the system structure, and the dynamic mathematical model in this method will directly affect the effect of network filtering. It is difficult to establish an accurate dynamic mathematical model, which limits the further improvement of control stability and bandwidth. improve.

Zhu Heng, Institute of Optoelectronics Technology, Chinese Academy of Sciences, and others proposed a high-speed piezoelectric tilting mirror based on thin-plate radial support. A thin-plate radial support was added at the connection between the lens and the driver to limit the radial offset and increase the axis. The axial stiffness effectively improves the overall stiffness distribution of the tilted mirror and increases the resonant frequency of the tilted mirror with the original structure. However, the structure is more complex, the installation requirements are higher, and the distance between the driving point and the rotation center of the mirror is small, which limits the angular resolution of the system.

In the invention patent "Beam Precision Pointing Device Based on Resolution Multiplier Compliant Mechanism" (Application No.: CN 101794020.A) filed by Fan Dapeng and others from National University of Defense Technology in 2010, they proposed a resolution multiplication lever structure, using multiplication The displacement of both ends of the lever changes proportionally to improve the angular resolution of the system. It has the characteristics of compact structure, high positioning accuracy, and high angular resolution. However, due to the parallel guiding compliance mechanism and the flexible hinge of the resolution multiplying lever are springs Chip structure, the response speed of the system is low, and it cannot be used when a fast response is required.

New mechanical beam deflectors mainly include eccentric lens type, rotating prism type, eccentric microlens array type, and controllable microprism array type.

The eccentric lens beam deflector proposed by J.Gibson et al. of Dayton University in the United States places two front and rear lenses on the confocal plane, the front lens is fixed, and the angle deflection of the outgoing beam is realized by the lateral translation of the latter lens relative to the previous lens. , compared with the traditional mechanical deflection structure, it has the characteristics of no rotating optical axis and large deflection angle (up to 45°); a national special reference device established by the former Soviet Union for straightness and flatness measurement is used. With the same structure, through the translation of the latter lens, the angle change of the incident beam relative to the optical axis is converted into the translation of the outgoing beam, so as to realize the angular deflection of the outgoing beam relative to the incident beam, so as to achieve the purpose of correcting the drift of the beam angle; J. Gibson et al. also proposed a rotating wedge prism beam deflector, in which two double glued adispersive wedge prisms are placed opposite each other, and the two wedge prisms take the incident beam as the rotation axis for circular rotation to realize the deflection of the outgoing beam direction; above Both beam deflectors can achieve a resolution of 1mrad, a deflection speed of 1rad/s, and a two-dimensional angular deflection range greater than 45°. Because the movement of the lens and wedge prism is used in the device to realize the beam deflection, the volume, quality and power consumption have not been improved, the response speed of the beam deflection is difficult to be improved, and the two-dimensional translation of the lens is easy to generate coupling. The rotational motion control of the two wedge prisms The process is more complicated.

A.Akatay and H.Urey of Koc University in Turkey proposed a high-resolution microlens array beam deflector made of binary optics, which consists of a pair of microlens arrays with a pitch of several microns. The group is a negative lens. The collimated light is focused by the positive lens, and then becomes collimated light by the negative lens. When there is a lateral relative movement between the positive and negative lens arrays, the direction of the outgoing collimated beam will be deflected. Using micro-optical components instead of traditional optical components can effectively reduce the volume, mass and power consumption of the beam deflection system. This kind of lens only needs a small relative displacement to produce a large angular deflection of the output beam. The smaller the lens array , the smaller the relative displacement required to achieve the same deflection, so the scanning rate of this scanner can be very high, but the scanning angle is relatively small (can reach several degrees), the transmittance is low, and the fabrication of micro-optical elements Technology is the key factor to determine its performance, and it is not yet mature in engineering applications.

N.R.Smith of the University of Cincinnati in the United States proposed a beam deflection device for electrowetting micro wedge prisms (EMPs). A liquid material with a certain refractive index is placed in the micro cavity, the liquid is grounded, and two electrodes are placed on both sides of the cavity. When different voltages are applied to the two polar plates, the upper surface of the liquid in the cavity will present slopes with different angles according to the voltage of the polar plates, and form a wedge angle with the bottom surface of the liquid, forming a micro-wedge with a controllable wedge angle. The prism changes the wedge angle of the micro-wedge prism by controlling the plate voltage on both sides of the cavity to realize the deflection control of the beam exit angle. In this method, the maximum deflection angle of the beam is related to the refractive index of the liquid material used. The realized beam deflection range can reach 30°, and the response speed is on the order of milliseconds. loss, the voltage between the electrode plates on both sides of the cavity wall needs to reach tens of volts, and in order to increase the beam deflection angle, it is necessary to increase the voltage difference between the electrode plates to increase the wedge angle of the liquid micro-wedge prism, while The distance between the electrode plates is on the order of micron to millimeter, so a very strong electric field is formed in the cavity, which is easy to cause breakdown, and the manufacturing process of the device is relatively complicated.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a high-response two-dimensional micro-angle pendulum control mirror based on a biaxial flexible hinge, so as to achieve fast dynamic response and realize two-dimensional micro-angle deflection at the same time .

The purpose of the present invention is achieved like this:

A high-response two-dimensional micro-angular pendulum control mirror based on a biaxial flexible hinge, a biaxial flexible hinge is fixed on the upper end surface of the base, a rigid platform is placed vertically on the output end of the biaxial flexible hinge, and the The flexible hinge produces two-dimensional micro-angle deflection, and the two-dimensional deflection mechanism is composed of the base, the biaxial flexible hinge and the rigid platform; Shaft; the driving mechanism is composed of four piezoelectric ceramic drivers, corresponding piezoelectric ceramic drive power supplies and fasteners, of which the four piezoelectric ceramic drivers are evenly distributed on the base through fasteners, and the corresponding two The piezoelectric ceramic drivers constitute a group, and the two groups of piezoelectric ceramic drivers are respectively arranged symmetrically with respect to the orthogonal deflection axes of the biaxial flexible hinge; four displacement sensors and a computer system constitute a control system, and the four displacement sensors are relatively The shaft flexible hinge is symmetrically assembled on the base and is in contact with the rigid platform; the wires respectively connect the displacement sensor with the computer system host, the computer system host with the piezoelectric ceramic driving power supply, and the piezoelectric ceramic driving power supply and the piezoelectric ceramic driver.

The piezoelectric ceramic driver and the piezoelectric ceramic driving power in the high-response two-dimensional micro-angular pendulum control mirror based on the biaxial flexible hinge are respectively an electrostrictive driver and a driving source, or a magnetostrictive driver and a driving source, Or a voice coil motor driver and drive source.

The displacement sensor in the high-response two-dimensional micro-angular pendulum control mirror based on the biaxial flexible hinge is a capacitive sensor, or an inductive sensor, or an eddy current sensor.

Notable features and advantages of the present invention are:

1. The present invention uses a biaxial flexible hinge to realize the micro-angle deflection in the two-dimensional orthogonal direction. The biaxial flexible hinge does not produce angular coupling and interference in the two-dimensional orthogonal deflection direction, and can produce accurate and highly sensitive micro-angular displacement;

2. In the present invention, in the two-dimensional deflection direction, dual drivers are used to drive synchronously in the forward and reverse directions at symmetrical positions, so that the mirror can have high-speed and no-lag dynamic tracking response characteristics; by optimizing the width and thickness of the biaxial flexible hinge, The fully consistent response characteristics can be obtained during two-dimensional deflection; and the great axial stiffness of the biaxial flexible hinge can limit the axial displacement of the mirror during deflection.

Description of drawings

Fig. 1 is a schematic diagram of the overall assembly structure of the present invention;

Fig. 2 is a schematic diagram of the overall disassembly structure of the present invention;

Fig. 3 is a schematic diagram of the assembly and connection structure of the base, the biaxial flexible hinge and the rigid platform in Fig. 1;

Figure 4 (a) is the y-direction front view of the assembly connection structure of the base, biaxial flexible hinge and rigid platform in Figure 1, and (b) is the x-direction front view of the assembly connection structure of the base, biaxial flexible hinge and rigid platform in Figure 1 ;

Part number description in the figure: 1. Mirror, 2. Rigid platform, 3. Piezoelectric ceramic driver, 4. Base, 5. Biaxial flexible hinge, 6. Displacement sensor, 7. Fastener, 8. Piezoelectric ceramic Drive power supply, 9. Computer system.

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

A high-response two-dimensional micro-angle pendulum control mirror based on a biaxial flexible hinge, a biaxial flexible hinge 5 is fixed on the upper surface of the base 4, and a rigid platform 2 is vertically placed on the output end of the biaxial flexible hinge 5. And a two-dimensional micro-angle deflection occurs around the biaxial flexible hinge 5, and the two-dimensional deflection mechanism is composed of the base 4, the biaxial flexible hinge 5 and the rigid platform 2; the reflector 1 is fixed on the upper end surface of the rigid platform 2, and the reflector 1, The rigid platform 2, the biaxial flexible hinge 5 and the center of the base 4 are coaxial; the driving mechanism is composed of four piezoelectric ceramic drivers 3, corresponding piezoelectric ceramic driving power sources 8 and fasteners 7, of which the four piezoelectric ceramic drivers 3 The fasteners 7 are evenly distributed on the base 4, and the corresponding two piezoelectric ceramic drivers 4 form a group, and the two groups of piezoelectric ceramic drivers 4 are respectively symmetrical to the orthogonal deflection axes of the biaxial flexible hinge 5 Setting; four displacement sensors 6 and a computer system 9 constitute a control system, and the four displacement sensors 6 are symmetrically mounted on the base 4 relative to the biaxial flexible hinge 5, and are in contact with the rigid platform 2; The sensor 6 communicates with the computer system 9 host, the computer system 9 host communicates with the piezoelectric ceramic driving power 8 , and the piezoelectric ceramic driving power 8 communicates with the piezoelectric ceramic driver 3 .

The piezoelectric ceramic driver 3 and the piezoelectric ceramic driving power source 8 are respectively an electrostrictive driver and a driving source, or a magnetostrictive driver and a driving source, or a voice coil motor driver and a driving source.

The displacement sensor 6 is a capacitive sensor, or an inductive sensor, or an eddy current sensor.

During operation, when the reflector 1 needs to be deflected by a certain spatial angle (α _x , α _y ), the control system controls the four output voltages of the piezoelectric ceramic power supply 8 to respectively drive four piezoelectric ceramic drivers 3, and the piezoelectric ceramic driver 3. The distance between the driving point on the rigid platform 2 and the center of the rigid platform 2 is L. Four piezoelectric ceramic actuators 3 are placed in groups of two, and they are respectively placed symmetrically with respect to the orthogonal deflection axes of the biaxial flexible hinge 5. In each group The two piezoceramic drivers 3 work in a differential manner, that is, one produces a positive displacement, and the other produces a negative displacement. The two displacements are the same, and the directions are opposite. The displacements are respectively: sx=L×tanα _x , s _y = L×tanα _y . The piezoelectric ceramic driver 3 pushes the rigid platform 2 to cause the mirror 1 to deflect in a spatial angle around the center, and the four displacement sensors 6 work in a differential manner in groups of two, and feed back the rotation angle information of the rigid platform 2 to the computer system 9, The computer system 9 controls the displacement outputted by the piezoelectric ceramic driver 3 in real time according to the rotation angle information fed back by the displacement sensor 6 , so as to precisely adjust the deflection angle of the mirror 1 . The invention has two-dimensional light beam deflection control capability, deflection in the two-dimensional direction has no coupling and axial translation, and has the same dynamic fast tracking response capability in the two-dimensional direction.

Claims (2)

1. A high-response two-dimensional micro-angular pendulum control mirror based on a biaxial flexible hinge, characterized in that: a biaxial flexible hinge (5) is fixed on the upper end surface of the base (4), and the rigid platform (2) is vertical Placed on the output end of the biaxial flexible hinge (5), and two-dimensional micro-angle deflection occurs around the biaxial flexible hinge (5), consisting of a base (4), a biaxial flexible hinge (5) and a rigid platform (2) Two-dimensional deflection mechanism; the reflector (1) is fixed on the upper end surface of the rigid platform (2), and the reflector (1), rigid platform (2), biaxial flexible hinge (5) and the center of the base (4) are coaxial; The driving mechanism is composed of four piezoelectric ceramic drivers (3), corresponding piezoelectric ceramic driving power sources (8) and fasteners (7), among which the four piezoelectric ceramic drivers (3) are connected through the fasteners (7). The cloth is mounted on the base (4), and the corresponding two piezoelectric ceramic drivers (4) form a group, and the two groups of piezoelectric ceramic drivers (4) are respectively relative to the orthogonal deflection of the biaxial flexible hinge (5). The shafts are arranged symmetrically; four displacement sensors (6) and a computer system (9) constitute a control system, and the four displacement sensors (6) are symmetrically mounted on the base (4) relative to the biaxial flexible hinge (5), And it is in contact with the rigid platform (2); the wires respectively connect the displacement sensor (6) to the computer system (9) host, the computer system (9) host to the piezoelectric ceramic driving power supply (8), and the piezoelectric ceramic driving power supply (8) It communicates with the piezoelectric ceramic driver (3). 2. The high-response two-dimensional micro-angular pendulum control mirror based on a biaxial flexible hinge according to claim 1, characterized in that the displacement sensor (6) is a capacitive sensor, or an inductive sensor, or an eddy current sensor.

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